Copying machine

ABSTRACT

An electrostatic copying machine capable of very fast operation in a reciprocating multiple copy mode. The original document to be copied is transported through the machine past the scanning window. After a first copy has been made the document itself is shuttled back past the scanning window until the leading edge of the original is at the front end of the scanning window. At this time another forward movement and scan take place, and another copy is made. This process is repeated for as many times as the number of copies required. The overall operation is fast for two reasons. First, the reverse feed rate of the original is greater than the forward feed rate since during reverse feed there is no scanning. Second, the copy paper feed begins during the reverse travel of the original such that by the time the leading edge of the original reaches the front end of the scanning window, the leading edge of the copy paper reaches the front end of the exposure window and exposure can proceed without lost time. During forward feed the original is moved only until the trailing edge clears the scanning window. During reverse feed the original is moved only until the leading edge clears the scanning window. The use of a cam which can be clutched to the original drive system permits the copy feed to start at a time such that perfect registration is assured when the original forward feed begins, independent of the length of the original.

United States Patent [72] Inventors John A. Van Auken Miami Beach;Lionel B. Hoffman, Fort Lauderdale; M. Gene Kaufman, South Miami, Fla.

[2]] Appl. No. 725,390

[22] Filed Apr. 30, 1968 [45] Patented Apr. 20, 1971 [73] AssigneeCopystatics Manufacturing Corp.

Miami Lakes,Fla.

[54] COPYING MACHINE 39 Claims, 6 Drawing Fig Primary Examiner-Samuel S.Matthews Assistant Examiner-Russell E. Adams, Jr. Attorney-Amster andRothstein ABSTRACT: An electrostatic copying machine capable of veryfast operation in a reciprocating multiple copy mode. The originaldocument to be copied is transported through the machine past thescanning window. After a first copy has been made the document itself isshuttled back past the scanning window until the leading edge of theoriginal is at the front end of the scanning window. At this timeanother forward movement and scan take place, and another copy is made.This process is repeated for as many times as the number of copiesrequired. The overall operation is fast for two reasons. First, thereverse feed rate of the original is greater than the forward feed ratesince during reverse feed there is no scanning. Second, the copy paperfeed begins during the reverse travel of the original such that by thetime the leading edge of the original reaches the front end of thescanning window, the leading edge of the copy paper reaches the frontend of the exposure window and exposure can proceed without lost time.During forward feed the original is moved only until the trailing edgeclears the scanning window. During reverse feed the original is movedonly until the leading edge clears the scanning window. The use -of acam which can be clutched to the original drive system permits the copyfeed to start at a time such that perfect registration is assured whenthe original forward feed begins, independent of the length of theoriginal.

PATENIED APR20 197i SHEET 1 OF 4 ATTORNEYS PATENIEU M2019?! SHEET b 0F 4.SIV-E SW-L FIG. 6.

ATTORNEYS COPYING MACHINE This invention relates to copying machines,and more particularly to an improved multiple copy mode of operation foran electrostatic copying machine.

There are two types of arrangements for controlling the scanning of anoriginal document to be copied by an electrostatic copying machine. Inthe first type, the document is held stationary and an optional systemis moved across it for the purpose of scanning it section by section.This type of arrangement has the obvious disadvantage of the need toprovide the necessary mounting for the movable optical system. ln thesecond type, the original document is moved past a stationary opticalsystem, section by section of the document being scanned as it movespast the optical system. Various difficulties have also been encounteredin the design of machines of this type.

Two approaches have been taken in the design of movable documentmachines. In one, the original document, book, etc. is placed on aplate, the plate being moved past the. stationary optical system duringthe scanning. in order to make multiple copies of an original document,the plate is shuttled back and forth past the optical system, theoptical system scanning the original document each time a forward passis made. One of the disadvantages of the shuttling-plate technique isthat each time a new document is to be copied the previous original mustbe removed from the plate and the new originalmust be placed on it. Thiscan be very time consuming especially if only a single copy is requiredof each of many originals.

The second approach which has been taken in movable document machines isto provide for the feeding in of an original document to be copied. Theoperator need merely feed in one document after. another withoutremoving each original from the machine after a copy is-made of it.Instead, all of the original documents are fed through the machine intoa collecting tray. The problem with this technique relates to multiplecopying. Once the operator has fed in a document to be copied, it is outof his control. Yet the document must be moved past the stationaryoptical system a number of times in succession. This has been achievedby. transporting the document in a closed loop, the optical system beingplaced along one section of the loop. The original document traversesthe loop once for each copy required. After the requisite number ofcopies have been made, the original document: is directed out of theloop to the collecting tray.

However, this circulating type system is also disadvantageous in anumber of respects. The loop must be long enough to accommodate thelongest original document to be copied. If in a particular case a shortdocument is being copied, a considerable amount of time is wasted as theshort document traverses a lengthy loop. Also, in such a closed loop itis very important that all of the feed rollers be in perfectparallelism. If they are not, there will be a tendency for the originalto be displaced sidewise relative to the path direction with anattendant loss of registration, and possibly jamming of the original.Finally, not only is it possible for the original document to be bent asit traverses the loop, there is a limit to the thickness of the originalwhich can be passed through the machine. For example, cardboard postersare generally incapable of being passed through such a machine for thepurpose of copying a particular page.

It is the general object of this invention to speed up the operation ofa copying machine in the multiple copy mode, and to overcome theaforesaid problems.

Briefly, in accordance with the principles of our invention, theoriginal document itself is shuttled back and. forth past a stationaryoptical system. During each forward pass of the original, the documentis scanned and another copy is made. After the last copy is madethedocument is discharged from the machine into a collecting tray andanother document to be copiedcan be inserted. Because this reciprocatingoriginal feed does not impart any bend to the original as it passesthrough the machine, the original comes .out of the machine insubstantially the same condition as it went into it. The

machine can operate on a thicker original because the original ismaintained in a substantially planer position during both forward andreverse feeds. Finally, it is not as crucial that all of the rollerpairs in the planar path be in perfect parallelism. Since the documentretraces its original path there is substantially no cumulative error,and furthermore most minor errors which are introduced during theforward feed are compensated for as the document goes back through thesame rollers.

In any duplicating machine of the types described, the time required tomake each copy when a number of copies are being made is to a greatextent dependent upon the time required to return the optical system toits initial position (in the case where the original remainsstationary), or to return the original to its starting position (in thecase where the optical system remains stationary). In theclosed-loop'system the return" time is that time required for theoriginal to go all around the loop from the end of the original scanningwindow back to the beginning of the window. In the systemof ourinvention, the return time is the time required to move the original inthe reverse direction back past the scanning window. In the illustrativeembodiment of our invention, multiple copying is speeded up by providingfor a return feed rate which is greater than the forward feed rate ofthe original.

The illustrative embodiment of the invention is a machine of the type inwhich the copy paper is contained on a roll. Sheets of copy paper arecut off from the roll dependent upon the length of each original to becopied. In a typical machine of this type, a sensor is disposed in thepath of the original in front of the scanning window for detecting theleading and trailing edges of the original. When the sensor firstdetects the leading edge of the original, copy paper is drawn from thecopy paper roll to supply copy paper to the copy exposure window. Whenthe sensor detects the trailing edge of the original, a knife isoperated to cut the copy paper which had been previously fed from theroll. At the same time, the copy paper feed stops. In order to insurethat the forward edge of the copy paper reaches the copy exposure windowat the same time that the forward edge of the original reaches thescanning window, it has been the practice to place the sensor at adistance in front of the scanning window equal to the distance of theknife in front of the exposure window. In our invention, as describedabove, it would appear that to make multiple copies it is necessary tomove the original all the way back such that the forward edge of theoriginal is adjacent the sensor. At this time the forward feed couldbegin together with the copy roll feed, (References in this descriptionand the claims to forward edges of the scanning and exposure windowsrefer to those points in the travel paths where exposure of the copypaper actually begins. in the illustrative embodiment of the inventionexposure begins when the original and copy paper reach the physicaledges of the respective Windows. In other cases, where the windows areenlarged, it is the point in each travel path where exposure actuallybegins and copy synchronization is achieved that must be takenintoaccount and should be considered as the forward edge" of therespective window).

In the illustrative embodiment of our invention, however, in order tospeed up multiplecopying, the original is not moved all the way backuntil its forward edge is adjacent thesensor. To this end a timing camis provided which can be driven from thedrive chain which operates thefeed rollers for the original. The cam is clutched'to be driven from thedrive chain during its travel past the scanning window. When thetrailing edge of the original has passedthe scanning window, thechain-drive is reversed so that the original isvfed in the reversedirection through the machine. During the reverse movement of theoriginal, the timing cammoves in its reverse direction. The timing camcontrols the, start of the copy rollfeed while the original is stillbeing returned past the scanning window. The

leading edge of the original is returned only to the forward edge of thescanning window, at which time it changes direction and-startsmoving inthe forward direction. By this time the leading edge of the copy paperhas reached the exposure window so that perfect registration of theoriginal and copy paper is assured. In this way, the multiple copy modeis further speeded up because it is not necessary to return the leadingedge of the original all the way back to the sensor which controls thecopy roll feed during the single copy mode. During multiple copying, thesensor controls only the cutting of the copy paper (when the trailingedge of the original is detected); the start of the copy roll feed iscontrolled by the timing cam, not the sensor.

It is a feature of our invention to shuttle an original document backand forth past a scanning window when making multiple copies.

It is a further feature of our invention to return the original documentpast the scanning window at a rate faster than the forward feed rate ofthe document.

It is a further feature of our invention to provide a timing cam whichcan be clutched to the original forward and reverse feed mechanism forrepresenting the position of the leading edge of the original.

It is a still further feature of our invention to start the copy rollfeed during reverse movement of the original in accordance with thereturn of the timing cam.

Further objects, features and advantages of the invention will becomeapparent upon consideration of the following detailed description inconjunction with the drawing, in which:

FIG. 1 depicts schematically (partially broken away) the arrangement ofvarious mechanisms in a copying machine employing the principles of ourinvention;

FIG. 2 is a view, with the housing removed, of the other side of thecopying machine of FIG. 1, showing the various drive chains for movingthe original and copy sheets;

FIG. 3 is a schematic diagram illustrating a control circuit forgoverning the operation of the machine of FIGS. I and 2 in accordancewith the principles of the invention; and

FIGS. 4, 5 and 6 depict the arrangement of various cams and switchesused in the system of FIGS. I3.

GENERAL DESCRIPTION OF MACHINE OPERATION The copy paper used in theillustrative embodiment of the invention is electrophotographic innature. It has the ability to retain an electric charge placed on itsphotoconductive coating by an electrostatic field. The coating can bedischarged by the application of light. Typically, copy paper roll 33(FIG. 1) consists of a base paper with photoconductive zinc oxideparticles dispersed in a resin coating. An electrical charge is placedon the front and back surfaces of the zinc oxide coating. When lightstrikes the zinc oxide particles they become conductive and the chargedsurfaces are neutralized.

As the leading edge of copy paper roll 33 passes through rollers 35, 36,39, 40 and 41, 42, the paper passes through the corona shields 43, 44which house two sets of very fine wire elements (not shown) across whichis placed a high DC voltage supply. The negative wire elements arecontained within shield 44 while the positive wire elements arecontained within shield 43. The shields aid in establishing the coronafield.

As the copy paper passes through the two sets of oppositely charged wireelements, a uniform negative charge is applied to the photoconductivecoating on the surface facing shield 44. A uniform positive charge isplaced on the surface of the coating facing shield 43. The chargesplaced on the surfaces of the copy paper will be retained for areasonable length of time provided it is not exposed to any light. Whenlight strikes the photoconductive coating, the zinc oxide particleswhich are exposed become conductive, neutralizing the negative andpositive charges in the exposed areas.

As the copy paper passes the exposure window consisting of a glasslesswindow strung with monofilament 64 and pressure member 23, thephotoconductive coating is exposed in accordance with dark and lightareas on the original to be copied. Rotary knife 38 cuts a copy sheetfrom the roll such that the cut sheet is the same length as the originalto be copied. When knife 38 operates, the copy roll paper feed stops,although the cut copy sheet continues to move past the exposure windowto trough 47 in the developing section of the machine.

The original document I2 is fed into the machine between rollers 9, 16which turn to move the original in the direction shown (from the rightend of the machine in FIG. 1 to the left end). As the original passesthe scanning window, on top of glass plate 22, light from two exposurelamps (shown in phantom in FIG. 1) within reflector 25 is reflected fromthe light image areas on the original along the dotted arrows 27 asshown. The light passes through lens system 28, assembly 30 and window64 to expose the copy paper. The copy paper feed is controlled such thatthe leading edge of the copy sheetjust reaches the exposure window whenthe leading edge of the original reaches the scanning window. The copypaper retains a negative charge in those areas corresponding to dark(image) areas on the original. The nonimage areas on the originalreflect a great deal of light to the surface of the copy paper causingthe neutralization of the charged areas corresponding to the nonimageareas on the original.

The copy sheet is then fed to trough 47. As shown in the drawing, theforward end of the copy paper has just entered the trough. The copysheet continues to travel along path 46 until the copy sheet is ejectedfrom the machine. In trough 47 there is a developer solution consistingof charged toner particles which are attracted to the negatively chargedimage areas on the copy paper. The attracted toner particles areimpregnated and fixed to the copy paper coating by a system of squeegeerollers and forced hot air drying.

The machine includes two basic systems of feed rollers or papertransport rollers, shown in FIG. 2 and to be discussed below. One systemis kept constantly rotating by a series of sprockets and drive chains,while the second system is clutchcontrolled so that it operates onlywhen one of two clutches is engaged.

When original document 12 is inserted between pickup rollers 9, 16 theoriginal is transported to the left in FIG. 1. As the leading edge ofthe original emerges from rollers 9, 16, it actuates photocell switch13. Each of photocell switches I3, 14, I5 is provided with a respectivelight source 21, 20, 19. When the leading edge of the original passesbetween a light source and its respective photocell switch, the changein state is registered and used to control the machine operation. Whenswitch 13 first operates, copy paper roller clutch K-6 (FIGS. 2 and 3)is energized to control copy paper insert rollers 35, 36 to rotate.These rollers pull the forward edge of the copy roll to direct the copypaper through the corona unit. The other rollers along the copy paperpath continuously operate. Initially, the forward edge of the copy paperis adjacent to knives 37, 38. Thus, although the rollers following theknives along the copy paper path rotate continuously there is no copysheet to be transported through the machine. But once rollers 35, 36start operating, copy paper is drawn from the roll into the copy papertransport system. The corona unit within shields 43, 44 charges thesurfaces of the copy paper. The original and the copy paper aresynchronized in their movements. The distance along the copy paper pathfrom the two knives to the forward end of the exposure window equal thedistance from photocell switch 13 to the forward end of the scanningwindow. Since the rollers along the original and copy paths move theoriginal and the copy paper at the same speed, and since the copy paperstarts to move past the knives under control of rollers 35, 36 just whenthe forward edge of the original is adjacent photocell switch 13, it isseen that the leading edges of the original and copy paper arrive at thescanning and exposure windows respectively at the same time. Thisinsures that the image formed on the copy will be in the same relativeposition as the image on the original.

As the trailing edge of the original passes photocell switch 13, thecopy paper roller clutch K-6 is disengaged. Rollers 35, 36 stop turningand copy roll 33 remains stationary. At the same time knife solenoid(FIG. 3) is energized to cause rotary knife 38 to cut the copy paper tothe exact length of the original. The cut sheet continues to betransported by the copy paper transport system through developer trough47. Intensifier drum 48 is constantly turned in the direction shown. (Itis possible to turn it in the opposite direction, and at various speedsas well). This insures that the copy paper is guided through thedeveloping trough. The developer solution itself is contained in tank 57which can be pulled out of the machine by handle 58. A pumping system(not shown) pumps the developer upward into trough 47.

The copy sheet then passes under deflector 56 toward the nip of squeegeerollers 53, 54. The squeegee rollers remove the excess liquid dispersantfrom the copy paper and to some slight degree also imbed the attractedtoner particles into the zinc oxide coated surface of the copy paper.Wiper 52 wipes metal squeegee rollers 53 to prevent tracking back" oroffsetting of a previous image, just as wiper 51 wipes intensifier drum48. The copy sheet is then forced down by the circulating air underdrier lamp 59 onto belt 61 which moves continuously around rollers 62,63, roller 62 being turned by the constantly rotating chain drive. Thecopy sheet is finally passed between belt 61 and plastic idler rollers55, several of which may be included on the same shaft, These rollersslightly crease the copy paper so that it will stack properly in thecopy receiving tray (not shown);

Blowers 23, 24 force air (shown by arrows 26) through the machine as iswell known in the art, for example, to dissipate the heat generated bythe exposure lamps. A series of guides 32 are provided for properlydirecting the air.

Shutter 31 can be moved up and. down from outside the machine (notshown) to adjust the time interval duringwhich each section of the copypaper is exposed. The lower the right end of the shutter, the larger theopening and the greater the exposure. The units shown symbolically onFIG. 1 are generally of types well known in the art and for the purposesof the present invention need not be gone into in any greater detail. Amachine constructed in accordance with the principles of our inventionincludes many mechanisms, controls and indicators, not shown in thedrawing. For example, various indicator lights may be provided to notifythe operator when additional developer solution is required or when anew roll of copy paper must be placed in the machine. The only controlshown in the drawing is that required for an understanding of thepresent invention, namely, the multiple copy selector dial 107 shown inFIGS. 1 and 5. This dial is marked in equal graduations numericallyrepresenting the number of copies desired. The selector dial can bereset at any time during machine operation providing for maximumflexibility. If the selector dial is allowed to remain in the normalposition (single copy mode) shown in FIG. 5, the machine will produceonly one copy for each original inserted into it. Any other positionwill provide the number of copiesas indicated by the selector dialsetting.

In the multiple copy mode, during the first cycle the original isscanned in the usual manner. Before it has travelled far enough to bereleased by the last set of rollers 7, 18, the trailing edge of theoriginal actuates photocell switch This causes the original transportroller system to reverse and return the original, at a speed greaterthan the forward speed, to the right toward the normal insertion point.When the leading edge of the original clears photocell 14, the originaltransport roller system is again normalized and transports'the originalto the left past the scanning window where it is scanned a second time(All references herein to leading and trailing edges of the original aremade respectively to the left edge of the original and the right edge ofthe original in FIG. 1. Thus, even when the original is beingtransported inv the reverse direction, the leading edge is stillconsidered to be the leftmost edge in FIG. 1.) This procedure isrepeated until the multiple copy selector dial 107 is counted down" tothe normal single copy mode position. The dialisdecremented one positionduring each reverse travel of the original. When all copies have beenmade except the last, the selector dial is fully decremented to thesingle copy mode position, at which time the machine will produce onemore copy and deposit the original in the original receiving tray.

To speed up the multiple copy operation, the original is returned onlyso far as to allow its leading edge to be adjacent to the forward end ofthe scanning window. Since the original immediately starts its forwardmovement, it is necessary for the leading edge of the copy sheet to beat the forward end of the exposure window by this time, i.e., the copyfeed must start while the original is still being moved in the reversedirection. In the single copy mode, the copy feed starts when photocelll3 detects the leading edge of the original. But in the multiple copymode, except during the first forward feed of the original, the leadingedge of the original does not pass photocell 13. For this reason analternate mechanism must be provided for initiating the copy feed duringreverse movementof the original.

Cam 106 (FIG. 6) is clutched to the original forward feed system whenthe leading edge of the original passes photocell switch 15. The camrotates counterclockwise as the original continues in the forwarddirection. When the original starts to move in the reverse direction,cam 106 starts restoring in the clockwise direction. The cam is fullyrestored when the leading edge of the original passes photocell 15 inthe reverse direction. But during the clockwise movement of cam 106,

some time prior to its full restoration, switch SW-Q is operated. Theoperation of the switch starts the copy paper feed. The leading edge ofthe original must yet travel back past photocell 15 (switch SW-Qoperates while the leading edge of the original is still to the left ofphotocell 15 in FIG. 1) and the scanning window to photocell 14. Theleading edge of the copy paper must travel from the knives to theforward end of the exposure window during the same time interval. Theoriginal reversefeed rate is greater than the copy feed rate. To assureproper registration of the original and copy at the scanning andexposure windows it is only necessary to have cam 106 operate switchS'W-Q at a point during the reverse movement of the original where theratio of the distance of the leading edge of the original from photocell14 to the distance between the knives and the exposure window is equalto the ratio of the original reverse feed rate to the copy feedrate. Inthis way the leading edge of the original will reach photocell 14' justwhen the leading edge of the copy sheet reaches the exposure window.

As soon as photocell l4 detects the leading edge of the original, theoriginal starts moving in the forward direction at the same speed as thecopy paper is moving. It is still necessary to cut the copy sheet. Thisis easily accomplished. The positions of the original and copy paper arethe same as though the machine were operating in the single copy mode.Consequently, when photocell 13 detects the trailing edge of theoriginal, it actuates the cutting mechanism and inhibits further feedfrom the copy paper roll. The length of the cut copy sheet during eachcycle in the multiple copy mode is thus the same as that ofthe original.

Referring to FIG. 2, when the main drive motor 72 is energized by thesystem on-olf switch (not shown) it rotates main drive sprockets 7lcounterclockwise. Main drive chain 74 is driven in a counterclockwisedirection by sprockets 7l. This chain turns various sprockets, includingtension adjustment idler sprocket 123' and the sprockets coupled torollers 42, 50, 53 and 62'. These four rollers turn continuously tomove: the copy paper. The fifth roller which is continuously turned inthe path of the copy paper is roller 40, coupled to a sprocket driven bydrive chain 73. Chain 73, like chain 74-, is'

driven by sprocket7l as long as the main power switch is clockwisedirection. Sprocket 76 rotates at a greater speed than that of sprocket79 because of its smaller diameter.

Chain 75 is the original transport drive chain. It is driven indirectlyby main drive chain 74 through an electrical clutch system. When forwardclutch K-7 (to be described in connection with FIG. 3) is energized,sprockets 78 and 79 are clutched together and sprocket 78 moves withcontinuously rotating sprocket 79. DRive chain 75 moves in the forward(F) direction, and since the diameter of sprockets 78 and 79 are thesame, chain 75 moves at the same speed as chain 74. Since the transportrollers have the same diameters, the original and copy sheets movethrough the machine at the same speed. Chain 75, in addition to movingover a tension adjustment idler sprocket Ill, drives the three sprocketscoupled to rollers 16, I7 and 18. Referring to FIG. 1, these are thethree driven rollers in the original transport system.

During multiple copying the original is first transported in a forwarddirection to be scanned and is then returned in the reverse direction athigh speed. This forward and reversing process continues as long as themachine remains in the multiple copy mode. When the original is beingreturned, forward clutch K-7 is deenergized and sprocket 78 is no longercoupled to sprocket 79. AT the same time reverse clutch K-8 (to bedescribed in connection with FIG. .3) is energized, which engagesreverse sprocket 77 with sprocket 76. Since sprocket 76 moves at afaster rate than sprocket 79, and sprocket 77 when clutched to sprocket76 moves at its rate, chain 75 moves in the reverse (R) direction at agreater speed than it does in the forward direction. With chain 75moving clockwise, rollers l6, l7 and 18 move in the reverse direction(opposite to that shown in FIG. I) to return the leading edge of theoriginal to the forward end of the scanning window. When this point isreached, the control circuits again change the driving direction ofchain 75 by deenergizing reverse clutch K-8 and energizing forwardclutch K-7.

Although chain 73 continuously drives the sprocket coupled to roller 40,as well as the three gears following it and terminating in gear 80,roller 35 does not rotate continuously. This is the roller which startsthe copy paper feed. Only when clutch K-6 is operated is roller 35coupled to gear 80. At this time copy paper feed begins.

The drive system is shown only schematically in FIG. 2, since the basicelements of such a drive system are well known. For example, it isunderstood that chain 74 can be used to drive any other elements whichmust be driven in the machine. The important thing to note in FIG. 2 isthe use of three clutches in connection with sprocket pairs 78, 79 and76, 77 and gear 80. The first clutch controls the forward movement ofthe original document. The second clutch controls the reverse movementof the original document at a faster speed. The third clutch controlscopy paper feed.

In the original transport system, rollers 16, 9 serve as the originalinput rollers, rollers 17, 8 serve as the scanner input rollers, androllers 18, 7 serve as the original exit rollers. As described above,rollers 16, 17 and 18 are driven by chain 75 in either direction.Rollers 7, 8 and 9 are contained in bridge assembly I] and are infriction contact with their respective lower rollers when bridge 1] isplaced on the machine. The bridge is removable so that in the event ofan original jam, it can be corrected with little difficulty. Photocellswitches l3. l4 and contained in bridge II are connected to the rest ofthe machine by contacts on bridge II. The bridge also includes apressure plate (not shown) for bearing against the original on top ofscanning glass 22. The spacing between the pressure plate and scanningglass 22 is several paper thicknesses.

An original collecting tray (not shown) is provided at the left end ofthe machine of FIG. I for collecting successive originals as they arefed through the machine. During multiple copying, the original isscanned in the forward direction in the usual manner, but before it isreleased by exit rollers 7, 18, all three pairs of transport rollers areautomatically reversed and the original is returned at high speed in thereverse direction.

The control circuit (FIG. 3) to be described below prevents a copy frombeing made while the original is being reversed. The original continuesto be transported in the reverse direction until the leading edge is tothe right of scanning window 22 at which time the control circuit againcauses the original to be transported in the forward direction to bescanned again. Photocells l4 and I5 are disposed at each end of thescanning glass and serve various functions to be described below.Photocell 13 serves to control the length of the cut copy sheet as wellas the copy paper feed.

Copy paper roll 33 is mounted on copy paper roll shaft 34. Although notshown, as is known in the art, provision is made for placing new copypaper rolls on the shaft as they are used up.

The operations of the original transport system during the single andmultiple copy modes are considerably different. However, with respect tothe copy transport system the operation is the same. Rollers 35, 36 andknife 38 control successive feedings of copy sheets into the copytransport system. The multiple copying mode operation will be describedin detail below after the control circuit of FIG. 3 is first describedwith respect to single mode operation.

DETAILED DESCRIPTION OF SINGLE COPY OPERATION Referring to FIG. 3, threeswitches, SW1, SW2 and SW3, are shown enclosed in three boxes 90, 91 and92. These switches are symbolic of the three photocells l3, l4 and 15and their associated amplifier circuitry in the original transportsystem. SWI corresponds to photocell I3, SW2 corresponds to photocell l4and SW3 corresponds to photocell 15. Each switch is normally open butcloses when the original passes under the respective photocell andblocks light from the respective one of light sources 19, 20 and 21. Theswitches are shown only symbolically since the construction of suchswitches are well known to those skilled in the art.

Before proceeding with a description of the operation of the controlcircuit shown on FIGS. 36, it is necessary to set forth the meaning ofthe various notations used on the drawing. On FIG. 3 there are fiverelays K] through K5. Each of these relays is normally deenergized. Eachrelay has a number of contacts, A, B, etc. For example, contact K3-D isthe fourth movable contact on relay K3. All of the contacts are shown inFIG. 3 in their normal positions with all five relays deenergized.

On FIG. 3 there are also four clutches K-6 through K-9. Clutch I(-6 isthe paper roller clutch which when energized causes copy paper rollers35 and 36 to operate. Clutch K-6 is shown on FIG. 2 as controllingrotation of roller 35. Clutch K-7 controls forward feed of the original,and when energized causes rollers l6, l7 and 18 to rotate in thedirections shown in FIG. 1. Clutch K-8 is the reverse clutch which whenenergized controls the reverse movement of the original. As seen in FIG.3, contact K4-C controls the energization of either clutch K-7 or clutchK-8. Finally, clutch K-9 when energized controls movement of cam 104 ofFIG. 6 in synchronism with original drive chain 75 (FIG. 2). This clutchis operated only during multiple copying.

R40 is the solenoid which when energized operates rotary knife 38 to cutthe copy paper.

On FIG. 3 there are also three timing motors TMl, TM2 and TM3. Whenenergized, these motors control movements of respective cams 95 (FIG.4), 102 and 103 (which comprise selector dial 107-FIG. 5), and 96 (FIG.4). These three cams, as well as cam 104 (FIG. 6), actuate variousswitches SW-A, SW-B, etc. Except for SW-A, each switch has twoterminals. With the cams in their normal positions as shown in FIGS. 4--6, some of the switches are open and some are closed. Switch SW-J, forexample, is closed, and as shown in FIG. 3 a connection is made throughthe two terminals of this switch to the winding of relay Kl. Others ofthe switches such as SW-L are open. As will be described below,rotations of the various cams control the opening of the normally closedswitches, and the closing of the normally open switches. Switch SW-A,unlike the others, has three contacts as shown in FIG. 4, and assimilarly shown in FIG. 3 in the circuit of timing motorTMl. In the restposition as shown in FIG. 4, SW-A is deactuated with a slight rotationof cam 95, the contact connections reverse and timing motor TMI isconnected to terminal LI in FIG. 3, bypassing contact KI-C.

As shown on the right side of FIG. 3, two rectifiers 93, 94 and atransformer 112 are provided for deriving two DC potentials, 24 voltsand 90 volts, across conductors 113-416. The various clutches and relayson FIG. 3 are connected between these DC potentials, while the threetiming motors are connected across the AC line terminals LI and L2.

When the leading edge of the original actuates switch SW l, theenergizing circuit for relay K1 is completed through normally closedswitch SW-N, switch SW1, normally closed switch SW-O, and normallyclosed switch SW-J. Closed contact K4-D bypasses switch SW() and part ofthe energizing current for relay K1 flows through this contact. With theenergization of relay K1 the copy paper roller clutch K-6 is operated,current flowing through the winding of the clutch and the now closedKl-D transfer contact. The corona charging system including a highvoltage rectifier (shown symbolically by numeral 89) is also energizedthrough thenow closed Kl-C contact, this contact connecting the coronacharging circuit to line terminal Ll.

At the same time, timing motor TMl starts operating with the closing ofthe KI-C contact. The motor circuit is completed from terminal Llthrough the Kl-C contact, switch SW-A, and normally closed switch SW-Bconnected to line terminal L2. Although switch SW-B is bypassed bycontacts Kl-A, KS-A and KZ-C, current does not flow through thesecontacts because contact Kl-A is open. The operation of motor TMI startsthe turning of cam-95on FIG. 4. The cam turns counterclockwise andassoon as-lobes 95a, 95b moves slightly, switches SW-E and SW-F close.Eachof these switches is connected in the energizing circuit for one'ofthe two exposure lamps (FIG. 3). In the illustrative embodiment of theinvention two such lamps are includedin reflector 25 (FIG. 1). MotorTMland cam 95 are provided to insure that the exposure lamps remain on fornot less than seconds. This is necessary since the lamps have a tendencyto darken on shorter duty cycles. As will become apparent below, cam 95turns l during each copying cycle. If timing motor TMI is not.interrupted, the cam turns. this amount within 5 seconds. In the case oflong originals, however, the timing motor is interrupted so that thelamps remain energized even longer.

As soon as lobe 95c moves slightly, switch SW-A changes position suchthat the energizing circuit for timing motor TMI bypasses contact KI-C.Thus, even after relay Kl releases, the timing motor can still operate.The motor continues to run until lobe 95b opens switch SW-B. Unlessrelays K1 and K2 are released at this time and contacts KI-A- and K2-Care closed, the energizing'circuit for TMI is broken.

With the closing of contact Kl-E, timing motor TM3 starts operating.This motor insures a cut copy length of not less than 8 inches and notmore than 20 inches. Provided that the length of the original is withinthese two limits the actual length of the cut copy will be identicalwith that of the original. Otherwise, a minimum length of 8 inches or amaximum of 20 inches is cut. The 8-inch minimum is to insure that thecut copy sheet has a sufficient length so as to at all times be drivenby rollers in the copy transport section. Otherwise, if the cut copy istoo short it may be trapped in the machine. The 20-inch maximum is toinsure that the copy sheet will not jam in the machine.

Cam 96 has two separate camming surfaces 97 and 98. Switches SW-H andSW-N are controlled by the lower camming surface 97. Switches SW--] and.SW-L are controlled by the upper camming surface 98. The lower cammingsurface 97 extends more than halfway around cam 96, while cammingsurface 98 extends only a fraction of the way around. With theenergization of timing motor TM3by the closing of contact Kl-E, cam 96starts to turn and switch SW-N opens. Although the original energizingcurrent for relay KI flowed through this contact, the relay remainsenergized because contact Kl-B is now closed and current flows throughit and contact SW-H. Even after switch SW-N opens, diode CR-l2 remainsnonconducting because it is shorted by the low resistance path throughswitch SWH. However, with the opening of switch SW-H, current flowsthrough closed contact Kl-B and the diode, and through switch SW1, theparallel circuit including switch SW-Q and contact K4-D, and switchSW-J.

The purpose of this circuit is to insure the minimum copy length of 8inches. By the time camming surface 97 turns sufficiently to open switchSW-H, at least 8 inches of copy. paper have been fed into the copytransport system. Relay Kl cannot release before this minimum feed hasoccurred, and since knife solenoid K,-l0 cannot operate until relay Klreleases, the, minimum length cut copy sheet is 8 inches. Only afterswitch SW-I-I opens does diode CR'12 conduct, and

only then does the opening of switch SW1 control the knife operation.

As soon as cam 96 starts to rotate, camming surface 98 allows switchSW-L to close. Although this switch is in the energizing circuit forknife solenoid K-l0, the knife solenoid does not operatev becausetransfer contact Kl-D is no longer connected in the circuit.

Relay KI remains energized until the trailing edge of the originalclears switch SW1 (assuming that switch SW-H has by this time opened).Contact Kl-D restores to the position shown in FIG. 3, clutch K-6releases, rollers 35, 36 stop tuming, and no more copy paper is fed fromroll 33. Similarly, the return of contact Kl-D completes the energizingcircuit for knife solenoid K-lt), switch SW-L having closed as soon ascam 96 started to turn. Rotary knife 38 rotates in the counterclockwisedirection and the copy sheet is cut from the copy paper roll.

Since contact Kl-D completes the energizing circuit for both copy paperclutch K-6 and knife solenoid K-l0, the paper roll feed stops slightlyprior to the operation of the knife. This could present seriousdifficulty (the copy paper transport system would continue to draw paperwhile no more could be fed past rollers 35, 36) were the followingcorrective measure not taken. The forward edge of the copy paper, whenit is first fed over rotary knife 38, continues to move upward until itstrikes the underside of deflector 66 (FIG. 1). The paper then movesunder the deflector toward rollers 39, 40, but the paper bears againstthe underside of deflector 66, not the upper surface of knife 38.Deflector 66 thus serves as a loop former," establishing some slack inthe copy paper between rollers 35, 36'and 39, 40. When rollers 35, 36stop turning, rollers 39, 40, which continue to rotate, take up theslack. The knife finishes its cut before most of the slack is taken up.

With the release, of relay K1 and the opening of contact KIE, timingmotor TM3 also deenergizes. Cam 96 is .connected by spring 100 to stop99. Pin I01 is included on the underside of the cam. As soon as TM3deenergizes, thespring causes cam 96 to restore in the counterclockwisedirection with the cam stopping when pin 101 hits stop 99. Cammingsurface 98 once again opens switch S W-L. The energizing circuit forknife solenoid K-IO is broken and knife 38 restores.

In the event the original is greater than 20 inches, camming surface 98opens switch SW-J after 20 inches of copy paper have been fed from roll33. The energizing circuit for relay K1. is broken, contact Kl-Drestores and the knife operates to cut off the maximum length of 20inches from the copy paper roll.

Cam 96 restores as though the trailing edge of the original had passedswitch SW1;

As the original continues to be transported toward the,

scanning window the leading edge actuates switch SW2 (actually, thisoccurs before the trailing edge passes switch SW1 and the knifeoperates). The closing of the switch energizes relay K2. Contact l(2Acloses to provide an alternate path for the corona charging systemthrough this contact and contact K4-F. Originally, the corona chargingcurrent flowed through contact Kl-C. Even after relay KI releases,however, the corona charging circuit remains energized as long as relayK2 is operated. This is necessary because were the corona chargingsystem to deenergize with the release of relay K1, the trailing portionof the cut copy sheet would not be charged.

Although contact I(2C opens with the energization of relay K2, this hasno effect on the running of timing motor TMI. The motor is held operatedby the current flowing through nonnally closed switch SW-B and nowtransferred switch SW-A.

As the original passes the scanning window, the copy paper is exposed.As the original continues to be scanned the leading edge actuates switchSW3. Although relay K3 energizes, it has no effect during single copymode operation. Similarly, its release at the end of the cycle has noeffect.

As cam 95 continues to rotate eventually one of the camming lobes opensswitch SW-B. (As shown in FIG. 4, it is lobe 95b which opens switchSW-B, although it is understood that a different lobe controls thisoperation during each cycle as the cam makes only one-third of arevolution during each copying operation.) With the opening of switchSW-B timing motor TMl stops operating. Cam 95 remains parked withswitches SW-E and SW-F still closed, thus keeping the two exposure lampson.

When the trailing edge of the original passes switch SW2, relay K2deenergizes. With the opening of contact K2-A the corona chargingcircuit deenergizes. (Contact Kl-C is by this time open since relay KIreleases before relay K2). Since the trailing edge of the copy paper isnow clear of the corona unit further charging is unnecessary. With therelease of relay K2, contact KZ-C closes. Since contact KS-A is alwaysclosed during the single copy mode, and contact Kl-A restored to itsclosed position with the release of relay Kl, timing motor TMI resumesoperating even though switch SW-B is still open. Cam 95 thus resumes itsrotation in the counterclockwise direction. Switches SW-E and SW-F arestill closed, however, because it is necessary to keep the exposurelamps energized until after the exposure process has been completed.

As soon as cam 95 rotates slightly further in the counterclockwisedirection, switch SW-B closes once again to provide an alternate currentcircuit for timing motor TMI. After cam 95 has rotated one-third of arevolution, with the lobes being in the positions shown in FIG. 4(although each has moved 120), switch SW-A reverses and assumes theposition shown in FIG. 3. At this time the timing motor turns offbecause contacts KI-C and KZ-A are open. Although cam 95 starts turningfrom its parked position when the trailing edge of the original passesswitch SW2 at the forward end of the scanning window, by the time cam 95has rotated from the parked position through the end of its one-thirdrevolution the original has been completely transported past thescanning window and the copy sheet has completely passed by the copyexposure window. With cam 95 in its initial position (although rotatedI20), switches SW-E and SW-F open and the two exposure lamps turnoff.

It should be noted that timing motor TMI stops operating and cam 95 isparked when switch SW-B is opened. The operation of the timing motor andthe rotation of cam 95 resume when the trailing edge of the originalpasses switch SW2 and relay K2 releases. With a short original it ispossible for relay K2 to release even before switch SW-B is opened. Insuch a case cam 95 is not parked. However, it requires 5 seconds for cam95 to rotate I and the two exposure lamps thus remain on for at least 5seconds during each copying cycle. (With an original shorter than thedistance between rollers 9 and 8, the orig'nal becomes trapped betweenthe rollers and it is necessary to lift the bridge in order to removethe document. Switch SW2 does not operate and a maximum length copysheet is cut. Since the original does not pass the scanning window thecopy sheet is not exposed and is transported out of the machine with noimage on it.)

The original and the copy are deposited in their respective trays asthey are passed through the machine. At the end of the process allswitches and relays are in the conditions shown in Hg. 3 and 4, with theexception of cam which has rotated However, since the cam has threesymmetrically positioned lobes, as far as the machine operation isconcerned the cam is in its initial position.

DETAILED DESCRIPTION OF MULTIPLE COPY OPERATION The number of copiesproduced is selected by the operator. The outer edge of the multiplecopy selector dial 107 (FIG. 5 is sequentially numbered in 16 equalgraduations, starting with I and progressing in the counterclockwisedirection up to I6. The normal or single copy mode position of themultiple copy selector dial is that in which the numerically designatedposition of l is as shown in FIG. 5. If the dial is in the normalposition the machine operates in the single copy mode. To select anyother number of copies, the dial is turned until the desired number isin the 12 oclock" position. The dial can be rotated or changed at anytimeduring the copying cycle.

During each reverse travel of the original, the dial is rotated oneposition in the counterclockwise direction by timing motor TMZ. Thiscounting down" or decrementing of the selector dial provides a visualindication of the number of copies which must yet be made. If theselector is not changed by the operator, the decrementing continuesuntil the dial is in the single copy mode position of FIG. 5. At thistime, the original is scanned for the last time after which it isdeposited in the original receiving tray just as it is during the singlecopy mode.

In the multiple copy mode, the functional sequence is the same as thatof the single copy mode except that when the leading edge of theoriginal actuates switch SW3 during the first scan cycle, a series ofcontrol circuits are activated. These control circuits reverse thenormal travel of the original transport system when the trailing edge ofthe original clears switch SW3. The original is reversed at high speed.The control circuits also prevent the machine from making a copy whilethe original is being reversed.

When the leading edge of the original clears switch SW2 during highspeed reverse, the transport system is again normalized so that theoriginal is transported in the forward direction to be scanned onceagain. This action is repeated until the multiple copy selector dial isdecremented to the I position at which time the last scan begins withthe machine operating in the single copy mode. The multiple copyselector dial has two camming surfaces 102 and 103. Camming surface I02has 16 detent positions equally spaced around the circumference of thecam. The actuating arm for switch SW-C rides on the camming surface.When the actuating arm is on a high portion of the camming surface(between detents) switch SW-C is closed. Each time camming surface 102is rotated the switch actuating arm drops into a detent and switch SW-Copens. When the timing motor TM2 is first energized camming surface 102starts to rotate in the counterclockwise direction. The actuating arm ofswitch SW-C moves to a high point on camming surface 102 to close theswitch. The control circuit that initially starts the timing motorrotation is dcenergized soon after the timing motor starts to operate,but if it is energized long enough the lock circuit" established by theclosing of switch SW-C insures the continued timing motor operationuntil the actuating arm drops into the next detent of camming surface102. At this time, timing motor TM2 stops operating.

Camming surface I03 has only one detent. The detent is located at aposition such that it will permit the actuating arm of switch SW-D whichrides on the camming surface to be in the detent only when the multiplecopy selector dial is in the single copy mode position. When actuatingarm is in the detent the switch is open. lt is switch SW-D whichcontrols the multiple copy mode sequencing circuits. When the selectordial is manually rotated to a position representing the number of copiesdesired, both surfaces of cams 102 and 103 are rotated. With switch SW-Dclosed the multiple copying operation ensues. But as the selector dialis decremented, switch SW-D opens when the numeral 1 on the dial is inthe l 2 oclock position. After the original is reverse transported forthe last time, the last of the required number of copies is made in thesame way that a single copy is made.

Up to the point when switch SW3 is first energized by the leading edgeof the original the operation in the multiple copy mode is the same asthat in the single copy mode. With the energization of switch SW3 andthe operation of relay K3, contact K3-D closes to energize relay K5.Current flows through contact K3-D, the relay coil, and switch SW-D,switch SW-D being closed by camming surface 103 when more than one copyis being made.

When contact KS-C closes current flows through the energizing coil ofclutch timer K-9. The operation of this clutch couples earn 104 (FIG. 6)to drive chain 75 (FIG. 2).

Cam 104 thus rotates in the forward (counterclockwise) direction asshown in FIG. 6. (Gearing, not shown, is provided to gear down the speedof cam 104 with respect to thedrive chain speed. Cam 104 makes less thana single revolution even for the maximum length original). Switch SW-Qis normally closed. As cam 104 continues to rotate in the forwarddirection, switch SW-Q opens in the energizing circuit for relay Kl.However, relay Kl remains energized. Although after 8 inches of copypaper have been fed into the machine switch SW-H is opened by cammingsurface 97 on cam 96, relay Kl remains energized by the current flowingthrough contact K1-B, diode CR12, switch SW1, contact K4-D and switchSW-J.

When relay K5 first energizes, contact K5-A opens. lt will be recalledthat in the single copy mode timing motor TMl first operates when relayK1 is energized and contact Kl-C closes. The timing motor continues tooperate until switch SW-B opens at which time the timing motor isparked. When relay K2 releases and contact K2-C closes (contact Kl-Ahaving closed earlier), the timing motor continues to operate until cam95 has turned through its one-third revolution. However, with relay. K5operated and contact KS-A open in the multiple copy mode, the timingmotor cannot resume operating when relay [(2 releases and contact K2-Ccloses. Consequently, the timing motor remains parked throughout themultiple copy mode. Switches SW-E and SW-F remain closed and the twoexposure lamps remain operated throughout the multiple copy cycle. It isonly when the last copy is being made and relay K5 is released becauseswitch SW-D is open that the last release of relay K2 allows timingmotor TMK to resume operation. Thus, even in the multiple copy mode cam95 turns through only 120 during the entire cycle.

With the leading edge of the original at photocell l5, relays K1, K2, K3and K5 are energized, the corona circuit is still energized throughcontact Kl-C, and through the alternate circuit including contact KZ-Aand K4-F, and the copy paper roll clutch K-6 is still energized throughthe Kl-D transfer contact. The exposure lamp timing motor TMl becomesparked as soon as cam 95 has rotated a sufiicient amount to open switchSW-B. Copy paper knife timingmotor TM3 is still operating since contactKl-E is closed. Switch SW-N is open and switch SW-L is closed. Assumingthat the length of the original is greater than 8 inches, switch SW-H isopen. Cam 104 continues to rotate in the forward direction.

The scanning and exposure process continues until the trailing edge ofthe original clears switch SW1 and relay Kl deenergizes. When contactKl-D restores to the position shown in FIG. 3, copy paper roller clutchK6 deenergizes to stop the copy paper feed. At the same time knifesolenoid K-l0 operates to cut the copy paper to the length of theoriginal. Since contact K1-E is now open, timing motor TM3 stopsoperating and spring returns cam 96 to the initial position. When switchSW-L opens, knife solenoid K-l0 releases. (Again, if the length of theoriginal is greater than 20 inches, camming surface 98 on cam 96operates switch SW-J thereby releasing relay Kl so that knife solenoidK-l0 operates to cut off a 20inch length of copy paper.)

With short originals, relay Kl releases before relay K5 operates sincethe trailing edge of the original passes'photocell 13 before the leadingedge reaches photocell 15. The operation is the same, however, exceptthat relay Kl does not deenergize until switch SW-H opens after aminimum length of 8 inches has been fed from the copy paper roll.

Although relay K1 is deenergized and contact Kl-C is open, contacts K2-Aand K4-F are still closed so that the corona charging system is stillenergized. Eventually the trailing edge of the original passes switchSW2 permitting relay K2 to deenergize. With the opening of contact K2Athe corona system is deenergized. Originally, relay K5 was energized bythe current flowing through contact K3-D. As will be seen below, relayK3 soon releases. However, with relay K2 deenergized, contact K2-B is inthe position shown in FIG. 3 and relay K5 is held energized by currentflowing through contact K2-B and contact K5-B. Although contact K2-Ccloses with the release of relay K2 (which causes timing motor TM] toresume operation in the single copy mode), because relay K5 is energizedand contact K5-A is open, timing motor TMl remains deenergized in themultiple copy mode.

The trailing edge of the original clears the scanning window glass atthe same instant that the trailing edge of the copy paper clears theexposure window opening. The scanning and exposure process is nowcomplete and the copy sheet is being developed. The copy sheet is thendeposited in the copy receiving tray. When the trailing edge of theoriginal clears switch SW3, relay K3 is deenergized. While relay K3 wasenergized, contact K3C was in its rightmost position. Since contact K4-Bwas open relay K4 could not operate. However, when contact K3-C restoresto its normal position relay K4 operates since at this time contact KS-Dis closed. With the energization of relay K4 a number of operations takeplace.

In the single copy mode, forward clutch K-7 is operated by currentflowing through contact K4-C to control the forward feed of theoriginal. Similarly, in the multiple copy mode relay K4 is initiallydeenergized and the original is fed in the forwaRd direction with theenergization of clutch K-7. But as soon as relay K4 energizes contactK4-C moves to its rightmost position in FIG. 3 to deenergize clutch K-7and to energize clutch K-8. At this time the original is fed in thereverse direction through the machine. As describedabove in connectionwith F IG. 2, the reverse feed is faster than the forward feed.

Originally, contacts K4-A and K3-A, and switch SW-C were open so thattiming motor TM2 could not operate. As soon as the trailing edge of theoriginal passes switch SW3, relay K3 releases and contact K3-A closes.Since relay K4 operates at the same time and contact K4-A closes,current flows through this contactand contact K3-A to timing motor TM2.The timing motor thus starts to turn the multiple copy shortintervalthat relay K3 is released. With switch SW-C still open when relay K3reenergizes, timing motor TM2.stops operating. The dial is notdecremented atthis time.

The first photocell to become deenergized during the reverse feed isphotocell 15 and relay K3 thus energizes. Relay;

K4 wasfirst operatedwhen relay K3 released and'contact K3C restored tothe initial position shown in H0. 3. Although contact K3-C now moves toits rightmost position, relay K4 remains energized by the currentflowing through contact K3C and contact K4-B. In order that contact K4-Bnot open during the switching of contact K3-C, relay K4 is preventedfrom releasing by current flowing through capacitor 110, this currentcontinuing to flow until contact K3-C restores. Relay K5 was originallyoperated with the energization of relay K3 and the closing of contactK3-D. Subsequently, the relay was alternately energized with the releaseof relay K2 and the restoring of contact K2-B to the position shown inFIG. 3. At the end of the forward feed, contact K3D opened with therelease of relay K3 but the alternate energizing path held relay K5operated. With the closing of contact K3-D at the start of the reversefeed, relay K5 is held on by currents through both paths.

The original continues to travel in its reverse direction. With relay K1deenergized and contact Kl-D in its normal position, clutch K4) is notoperated and there is no copy paper feed. Relay K5 is still energizedand contact K5-C is still closed, timer clutch K-Sl is still operatedand cam 104 is still coupled to drive chain 75. But since the drivechain is now moving in the reverse direction, cam 104 moves in itsreverse direction (clockwise). The cam, which at the end of the forwardfeed is in a position such as that shown by the numeral 106 in FIG. 6(the exact position depends on the length of the original), startsmoving toward its original position adjacent stop 105.

The original continues to be reverse transported and cam 104 continuesto be restored. The trailing edge of the original actuates switch SW2which results in the energization of relay K2. Although transfer contactKZ-B switches position, relay K5 is held operated through contact K3-D.Relay K4 is now held operated through its own contact K4-B, and bothcontacts K3-C and K2-B. The trailing edge of the original then actuatesswitch SW1. This has no effect on relay K1, however, since switch SWQ isopen, and because relay K4 is energized contact K4-D is open as well.(It should be noted that switch SW1 is bypassed anyway by closed contactK4-E, which condition similarly cannot control the energization of relayKl.) Eventually, cam 104 restores sufficiently to close switch SWQ.Current flows through switch SW-N, contact K4-E and switch SW1 inparallel, switches SWQ and SW-J, and the relay coil. With a shortoriginal the trailing edge may not control the closing of switch SW1 bythe time switch SW-Q closes. Bypassing contact K4-E is provided for thispurpose-relay K1 energizes with the closing of switch SW-Q even ifswitch SW1 has not yet closed. This is necessary because relay K1 mustoperate to start the forward feed when switch SW-Q closes for there tobe proper registration at the start of the next forward feed.

The actual time that relay K1 energizes as a result of the closing ofswitch SW-Q is variable, dependent upon the length of the original. Asdescribed above, timer clutch K-9 is energized with the closing ofcontact K5-C. This contact closes only when relay K5 energizes as aresult of the closing of contact K3-D, which contact closes with theenergization of relay K3 when the leading edge of the original actuatesswitch SW3. At this time drive chain 75 moving in the forward directionrotates cam 104 in the forward direction. When the trailing edge of theoriginal clears switch SW3, the rollers in the original transport systemare reversed. The timer clutch K-9 is still energized and consequentlycam 104 is driven in the reverse direction. Although the drive chainmoves at a faster speed in the reverse direction, the importantcriterion is the distance it moves. This distance is represented by thedistance previously moved through by cam 104.

Since cam 104 first started to move when the leading edge of theoriginal passed switch SW3, it would appear that switch SWQ closes andrelay Kl energizes only when the leading edge of the original is reversetransported past switch SW3. However, this is not the case. The cammingsurface of cam 104 is curved as shown in FIG. 6. Section 1040 of thecamming surface actuates switch SWQ during the reverse movement of cam104 even before the cam is fully restored to its initial position.Consequently, relay K1 is energized and the copy feed begins even beforethe leading edge of the original is adjacent switch SW3. The forwardfeed rate of the copy paper and the reverse speed rate of the original,as well as the shape of cam 104, are such that the leading edge of theoriginal reaches switch SW2 at the same time that the copy paper hasbeen fed into the machine an amount such that its forward edge reachesthe copy exposure window. The fact that switch SW-Q closes even beforecam 104 has completely restored allows the copy paper feed to begin evenbefore the leading edge of the original has been completely drawn backinto the machine. This allows for maximum copying speed since by thetime the leading edge of the original has cleared the scanning windowand is adjacent switch SW2, the leading edge of the copy paper isadjacent the exposure window and the forward feed of the original canstart immediately. The original need be reverse transported the minimumdistance, i.e., only until its leading edge just clears the scanningwindow.

With the closing of switch SW-() and the energization of relay K1, thecorona circuit is once again operated through contact Kl-C. Copy paperroller clutch K6 is also energized as a result of contact Kl-D moving tothe right. Similarly, knife timing motor TM3 starts operating with theclosing of contact Kl-E. lt is thus seen that with the closing of switchSW-Q, the copy feed cycle begins. While in the single copy mode the copyfeed begins when the leading edge of the original actuates switch SW1,such is not the case in the multiple copy mode. In the multiple copymode the copy feed starts when auxiliary feed switch SW-Q closes.

Eventually the trailing edge of the original actuates switch SW1 whichprovides an alternate current path around contact K4-E. Consequently,even after relay K4 deenergizes, relay Kl remains operated.

When the leading edge of the original clears switch SW3, relay K3deenergizes. With the opening of contact K3-D, relay K5 deenergizes.This in turn opens contact K5-C to release timer clutch K-9. By thistime cam 104 is in its initial position since the leading edge of theoriginal is adjacent switch SW3. Although contact K3-C restores, relayK2 is still energized and relay K4 remains energized by the currentthrough contacts K2-B and K4-B.

With relay K3 released and relays K2 and K4 operated, timing motor TM2starts operating once again. This time, however, relay K3 does notimmediately reenergize and cam 102 moves sufficiently to close contactSWC. Contact SWC is closed before relay K2 releases as the leading edgeof the original clears switch SW2. The closed contact keeps timing motorTM2 energized until the dial is decremented one position and the contactopens.

The original continues to move in the reverse direction until theleading edge clears switch SW2. Relay K2 deenergizes and with therestoring of contact K2-B relay K4 deenergizes. When contact K4Crestores, reverse clutch K-8 is deenergized and forward clutch K-7energizes. Thus, the leading edge of the original, which has justcleared the original scanning window and the adjacent switch SW2, startsmoving in the forward direction. Since at this time the leading edge ofthe copy paper is adjacent the forward end of the copy exposure window,perfect registration of the original and copy sheet is assured.

At this point in the operation relays K1 and K2 are energized and relaysK3, K4 and K5 are deenergized. As soon as relay K1 releases when thetrailing edge of the original passes switch SW1, the copy paper rollfeed stops and knife solenoid K-10 is actuated. The remainder of thecycle is the same as the first cycle. Similarly, subsequent cycles areidentical to the second cycle. The multiple copy selector dial isdecremented following each copy cycle. Eventually, the multiple copyselector dial is restored to the single copy position. Since switch SWDis then open (following the completion of the next-to-last copy cycle)and relays K4 and K cannot operate, the last copy cycle is the same asthat in the single copy mode, except for the fact that the copy paperfeed has already started during the last reverse travel of the original.

It is thus seen that multiple copies can be made very fast. Not only isthe original moved back through the machine at an increased speed, butthe copy paper feed starts even before the original has completelycleared the scanning window. The leading edge of the original is notrestored all the way to switch SW1. Instead, it is restored only to thefront edge of the scanning window. By providing clutched cam 104, theleading edge of the copy paper reaches the copy exposure window justwhen the leading edge of the original reaches switch SW2 at which timeforward feed of the original begins. The use of cam 104 allows the copypaper feed to begin even though the leading edge of the original isstill out of the machine. The machine need not detect the leading edgeof the original as it is withdrawn into the machine in order to startthe copy paper feed because the position of cam 104 in effect representsthe position of the leading edge of the original.

Although the invention has been described with reference to a particularembodiment, it is to be understood that this embodiment is merelyillustrative of the application of the principles of the invention. Forexample, precut sheets of copy paper can be used rather than a copypaper roll. In such a case, during multiple copying a sheet of copypaper would begin to be fed during the return of the original, and therewould be no need for a knife mechanism. Thus, numerous modifications maybe made in the illustrative embodiment of the invention and otherarrangements may be devised without departing from the spirit and scopeof the invention.

We claim:

1. A copying machine comprising a scanning window, roller means forengaging and transporting an original document to be copied in theforward direction past said scanning window, an exposure window, meansfor transporting copy paper past said exposure window in synchronismwith the forward movement of said original past said scanning window,means for scanning said original at said scanning window and in responsethereto for exposing said copy paper at said exposure window, and meansfor controlling said roller means to return said original in the reversedirection past said scanning window to permit another forward movementof said original past said scanning window and another exposure of copypaper at said exposure window in response thereto.

2. A copying machine in accordance with claim 1 wherein said rollermeans returns said original past said scanning window in said reversedirection at a speed greater than the speed of said original in saidforward direction.

3. A copying machine in accordance with claim 2 further including a rollof copy paper, means for initiating the feed of said copy paper fromsaid roll toward said exposure window at the speed of said original insaid forward direction responsive to the detection of the leading edgeof said original, and means for cutting a copy sheet from said roll andstopping the feed from said roll responsive to the detection of thetrailing edge of said original.

4. A copying machine in accordance with claim 3 further including meansfor automatically initiating the feed of said copy paper toward saidexposure window while said original is being transported in the reversedirection past said scanning window.

5. A copying machine in accordance with claim 4 further including meansadapted to be driven with said roller means responsive to the detectionof the leading edge of said original and for moving in a first directionwhile said original continues in its forward direction and forthereafter moving in a second opposite direction while said original ismoved in its reverse direction, and means responsive to the movement insaid second direction of said driven means for operating saidautomatically initiating means.

6. A copying machine in accordance with claim 4 further including meansfor representing the number of copies required of said original, meansfor decrementing said representing means responsive to each copy made bythe machine, and means for discharging said original from the machine inaccordance with the number represented by said representing means afterthe required number of copies have been made.

7. A copying machine in accordance with claim 6 wherein I said scanningmeans includes an exposure lamp, means for energizing said lamp beforethe leading edge of said original reaches the front edge of saidscanning window and for maintaining said lamp energized until thetrailing edge of said original has passed said scanning window, andmeans responsive to more than one required copy being represented bysaid representing means for preventing the deenergization of saidexposure lamp until after said original has passed said scanning windowfor the last time. s

8. A copying machine in accordance with claim 3 further including meansfor preventing the operation of said cutting means until a predeterminedminimum length of copy paper has been fed from said roll, and means forcontrolling the operation of said cutting means after a maximum lengthof copy paper has been fed from said roll independent of the detectionof the trailing edge of said original.

9. A copying machine in accordance with claim 3 further includingdeflector means for forming a slack portion in said copy paper betweensaid paper roll feed initiating means and said exposure window, saidslack being taken up during any interval between the stopping of saidfeed initiating means and the completion of the operation of saidcutting means.

10. A copying machine in accordance with claim 5 wherein said drivenmeans controls the operation of said automatically initiating means at atime during its movement in said second direction such that the ratio ofthe distance from the leading edge of said original to that point in itsforward path of movement where it becomes synchronized to movement ofsaid copy paper to the distance from said cutting means to that point inthe copy paper path of movement where said copy paper becomessynchronized to forward movement of said original is equal to the ratioof the reverse speed of said original to the forward speed of saidoriginal.

11. A copying machine comprising a scanning window, means forcontrolling the transport of an original document to be copied in theforward direction past said scanning window, an exposure window, meansfor transporting copy paper past said exposure window in synchronismwith the forward movement of said original past said scanning window,means for scanning said original at said scanning window and in responsethereto for exposing said copy paper at said exposure window, means forcontrolling the transport of said original in the reverse direction pastsaid scanning window to permit another forward movement of said originalpast said scanning window and another exposure of copy paper at saidexposure window in response thereto, said reverse transport controllingmeans being operative to control movement of said original past saidscanning window at a speed greater than the speed at which said originalmoves past said scanning window in the forward direction, and means forinitiating the operation of said copy paper transporting means whilesaid original is being transported in the reverse direction past saidscanning window at a time such that when said original starts to betransported in the forward direction the leading edges of said originaland said copy paper are in optical synchronization.

12. A copying machine in accordance with claim 11 further includingmeans adapted to be driven by said forward transport controlling meansin response to the detection of the leading edge of said original andfor moving in a first direction while said original continues in itsforward direction and for thereafter moving in a second oppositedirection while said original is moved in its reverse direction, andmeans responsive to the movement in said second direction of said drivenmeans for operating said initiating means.

13. A copying machine in accordance with claim 11 wherein saidinitiating means operates at a time during the reverse movement of saidoriginal such that the loading edge of said copy paper is insynchronization with the leading edge of said original at the same timethat the leading edge of said original moving in said reverse directionreaches the front edge of said scanning window, and further includingmeans responsive to the leading edge of said original reaching the frontedge of said scanning window for deenergizing said reverse transportcontrolling means and for enabling the operation of said forwardtransport controlling means.

14. A copying machine in accordance with claim it wherein said scanningand exposing means includes an exposure lamp, means for energizing saidlamp before the leading edge of said original reaches the front edge ofsaid scanning window and for maintaining said lamp energized until thetrailing edge of said original has passed said scanning window, andmeans responsive to more than one copy of said original being made bythe machine for preventing the deenergization of said exposure lampuntil after said original has passed said scanning window in the forwarddirection a number of times equal to the number of times equal to thenumber of copies being made.

15. A copying machine in accordance with claim '11 further including acopy paper roll, means for feeding paper from said copy paper roll tosaid copy paper transporting means, means for cutting a sheet from saidcopy paper roll and for stopping the feed of copy paper from said rollresponsive to the length of copy paper fed from said roll being equal tothe length of said original, means for preventing the operation of saidcutting and stopping means until a predetermine minimum length of copypaper has been fed from said roll, and means for controlling theoperation of said cutting and stopping means after a maximum length ofcopy paper has been fed from said roll independent of the length of saidoriginal.

16. A copying machine comprising a scanning window, means forcontrolling the transport of an original document to be copied in theforward direction past said scanning window, means for making a copy ofsaid original responsive to each forward pass of said original past saidscanning window, means for controlling the transport of said original inthe reverse direction past said scanning window in preparation for themaking of another copy, means for deenergizing said forward transportcontrolling means and for energizing said reverse transport controllingmeans responsive to the trailing edge of said original just clearing therear edge of said scanning window, and means for deenergizing saidreverse transport controlling means and for energizing said forwardtransport controlling means responsive to the leading edge of saidoriginaljust clearing the front edge of said scanning window.

17. A copying machine in accordance with claim 16 wherein said reversetransport controlling means controls the movement of said original at aspeed greater than the speed of said original controlled by said forwardtransport controlling means.

18. A copying machine in accordance with claim 17 wherein said copymaking means includes a supply of copy paper and means for initiatingmovement of a sheet of said copy paper during reverse movement of saidoriginal such that when said original starts moving in the forwarddirection said original and said copy sheet are in copy makingsynchronism.

19. A copying machine in accordance with claim 18 wherein said copymaking means includes an exposure window past which said copy sheetismoved, and said copy sheet movement initiating means operates at a timeduring the reverse movement of said original when the distance betweenthe leading edge of said original and that point in its forward path ofmovement where it becomes synchronized to movement of said copy sheetdivided by said reverse speed is equal to the distance between theleading edge of said copy sheet and that point in the copy sheet path ofmovement where said copy sheet becomes synchronized to forward movementof said original divided by the speed of movement of said copy sheet.

20. A copying machine comprising a scanning window, means forcontrolling the transport of an original document to be copied in theforward direction past said scanning window, means for controlling thetransport of said original in the reverse direction past said scanningwindow, an exposure window, means for transporting copy paper past saidexposure window, first means responsive to said original being firstinserted in the machine for initiating the transport of copy paper bysaid copy paper transporting means at a time such that the leading edgeof said original within said scanning window is in synchronization withthe leading edge of said copy paper within said exposure window, meansresponsive to the trailing edge of said original clearing said scanningwindow for deenergizing said forward transport controlling means and forenergizing said reverse transport controlling means, second means forinitiating the transport of copy paper by said copy paper transportingmeans during reverse movement of said original past said scanning windowprior to the clearing of said scanning window by said original, andmeans for deenergizing said reverse transport controlling means andenergizing said forward transport controlling means at a time whenforward movement of said original will cause it to be in synchronizationwith movement of said copy paper.

2]. A copying machine in accordance with claim 20 wherein said secondmeans operates at a time during reverse movement of said original whenthe leading edge of said original has not yet reached the rear edge ofsaid scanning window.

22. A copying machine in accordance with claim 21 wherein said reversetransport controlling means controls movement of said original past saidscanning window at a speed greater than the speed of said originalcontrolled by said forward transport controlling means.

23. A copying machine in accordance with claim 20 wherein said means fordeenergizing said reverse transport controlling means and for energizingsaid forward transport controlling means operates responsive to theleading edge of said original having just cleared the forward edge ofsaid scanning window in the reverse direction.

24. A copying machine in accordance with claim 21 wherein said means fordeenergizing said reverse transport controlling means and for energizingsaid forward transport controlling means operates responsive to theleading edge of said original having just cleared the forward edge ofsaid scanning window in the reverse direction.

25. A copying machine in accordance with claim 20 wherein said reversetransport controlling means controls movement of said original past saidscanning window at a speed greater than the speed of said originalcontrolled by said forward transport controlling means.

26. A copying machine in accordance with claim 25 wherein said means fordeenergizing said reverse transport controlling means and for energizingsaid forward transport controlling means operates responsive to theleading edge of said original having just cleared the forward edge ofsaid scanning window in the reverse direction.

27. A copying machine in accordance with claim 20 further including aroll of copy paper, said first and second initiating means controllingthe feed of copy paper from said roll to said copy paper transportingmeans, 'said first means being operative to initiate the feeding of copypaper from said copy paper roll responsive to the detection of theleading edge of said original, and means responsive to the detection bysaid first means of the trailing edge of said original for cutting thecopy paper fed from said roll and for stopping further feed of copypaper from said roll.

28. A copying machine in accordance with claim 27 wherein said secondmeans includes means adapted to be driven in synchronism with saidforward and reverse transport controlling means, means responsive to thedetection of the leading edge of said original for controlling theforward driving of said driven means in synchronism with said forwardtransport controlling means, said driven means thereafter being drivenin its reverse direction in synchronism with said reverse transportcontrolling means responsive to the energization of said reversetransport controlling means and the deenergization of said forwardtransport controlling means, and means responsive to the return of saiddriven means to predetermined point in its path of reverse movement forinitiating the feed of copy paper from said copy paper roll.

29. A copy machine in accordance with claim 28 wherein saidpredetermined point in the path of reverse movement of said driven meansis such that when said point is reached the leading edge of saidoriginal has not yet reached the rear edge of said scanning window.

30. A copying machine in accordance with claim 28 wherein said reversetransport controlling means controls reverse movement of said originalat a speed greater than the forward speed of said original controlled bysaid forward transport controlling means, said copy paper transportingmeans transports said copy paper at a speed equal to the forward speedof said original, and said predetermined point in the path of reversemovement of said driven means is such that between the time that saidpoint is reached and the time that said reverse transport controllingmeans is deenergized said original moves an amount in the reversedirection such that its subsequent forward movement is insynchronization with movement of said copy paper.

31. A copying machine in accordance with claim 30 further includingmeans for representing the number of copies required of said original,and means for discharging said original from the machine in accordancewith the number represented by said representing means after therequired number of copies have been made.

32. A copying machine in accordance with claim 27 further includingmeans for preventing the stopping of said paper feed from said roll andthe operation of said cutting means until a predetermined minimum lengthof copy paper has been fed from said roll, and means for controlling thestopping of said paper feed from said roll and the operation of saidcutting means after a maximum length of copy paper has been fed fromsaid roll independent of the detection of the trailing edge of saidoriginal by said first means.

33. A copying machine in accordance with claim 27 further includingmeans for forming a slack portion in said copy paper between saidcutting means and said exposure window, said slack being taken up duringany interval between the stopping of the feed of said copy paper rolland the completion of the operation of said cutting means.

34. A copying machine in accordance with claim 27 further includingmeans for representing the number of copies required of said original,and means for discharging said original from the machine in accordancewith the number represented by said representing means after therequired number of copies have been made.

35. A copying machine in accordance with claim 34 further including alamp for reflecting light from said original as it passes said scanningwindow toward said copy paper as it passes said exposure window, meansfor energizing said lamp before the leading edge ofsaid original reachesthe front edge of said scanning window, and means responsive only tosaid original having passed said scanning window in the forwarddirection a number of times-equal to the number represented by saidrepresenting means for deenergizing said lamp.

36. A copying machine comprising a scanning window, means forcontrolling the transport of an original document to be copied in theforward direction past said scanning window, means for controlling thetransport of said original in the reverse direction past said scanningwindow, an exposure window, means for transporting copy paper past saidexposure window, first means in the forward path of movement of saidoriginal document for sensing said original document when it is first isinserted in the machine to initiate the transport of copy paper by saidcopy paper transporting means at a time such that the leading edge ofsaid original within said scanning window is in s richronization withthe leading edge of said copy paper wit in said exposure window, meansfor scanning said original within said scanning window and exposing saidcopy paper within said exposure window, means operative after thescanning of said original and exposure of said copy paper are completedfor deenergizing said forward transport controlling means and forenergizing said reverse transport controlling means, second means forinitiating the transport of copy paper by said copy paper transportingmeans during reverse movement of said original past said scanning windowprior to the completion thereof, and means for deenergizing said reversetransport controlling means and energizing said forward transportcontrolling means at a time when forward movement of said original willcause it to be in synchronization with movement of said copy paper.

37. A copying machine in accordance with claim 36 wherein said means fordeenergizing said reverse transport controlling means and energizingsaid forward transport controlling means operates prior to return of theoriginal to that position at which said first means is operative whensaid original is first inserted in the machine.

38. A copying machine in accordance with claim 36 further including aroll of copy paper, said copy paper transporting means including meansfor feeding copy paper from said roll and means for moving copy paperfed from said roll to said exposure window, means responsive to theoperation of said first means for operating said copy paper feedingmeans, means disposed between said feeding means and said moving meansfor cutting a copy sheet from copy paper fed from said roll, means forinhibiting the operation of said feeding means and controlling theoperation of said cutting means such that the length of the cut copysheet is equal to that of the original, and deflector means for forminga slack portion in said copy paper between said cutting means and saidexposure window, the total slack portion formed being at least as greatas the slack taken up during any interval between the stopping of saidfeeding means and the completion of the operation of said cutting meansto permit continued normal operation of said moving means while saidcopy paper is being cut.

39. A copying machine in accordance with claim 38 wherein said feedingmeans is a pair of rollers and said moving means includes a pair ofrollers disposed between said exposure window and said deflector means.

1. A copying machine comprising a scanning window, roller means forengaging and transporting an original document to be copied in theforward direction past said scanning window, an exposure window, meansfor transporting copy paper past said exposure window in synchronismwith the forward movement of said original past said scanning window,means for scanning said original at said scanning window and in responsethereto for exposing said copy paper at said exposure window, and meansfor controlling said roller means to return said original in the reversedirection past said scanning window to permit another forward movementof said original past said scanning window and another exposure of copypaper at said exposure window in response thereto.
 2. A copying machinein accordance with claim 1 wherein said roller means returns saidoriginal past said scanning window in said reverse direction at a speedgreater than the speed of said original in said forward direction.
 3. Acopying machine in accordance with claim 2 further including a roll ofcopy paper, means for initiating the feed of said copy paper from saidroll toward said exposure window at the speed of said original in saidforward direction responsive to the detection of the leading edge ofsaid original, and means for cutting a copy sheet from said roll andstopping the feed from said roll responsive to the detection of thetrailing edge of said original.
 4. A copying machine in accordance withclaim 3 further including means for automatically initiating the feed ofsaid copy paper toward said exposure window while said original is beingtransported in the reverse direction past said scanning window.
 5. Acopying machine in accordance with claim 4 further including meansadapted to be driven with said roller means responsive to the detectionof the leading edge of said original and for moving in a first directionwhile said original continues in its forward direction and forthereafter moving in a second opposite direction while said original ismoved in its reverse direction, and means responsive to the movement insaid second direction of said driven means for operating saidautomatically initiating means.
 6. A copying machine in accordance withclaim 4 further including means for representing the number of copiesrequired of said original, means for decrementing said representingmeans responsive to each copy made by the machine, and means fordischarging said original from the machine in accordance with the numberrepresented by said representing means after the required number ofcopies have been made.
 7. A copying machine in accordance with claim 6wherein said scanning means includes an exposure lamp, means forenergizing said lamp before the leading edge of said original reachesthe front edge of said scanning window and for maintaining said lampenergiZed until the trailing edge of said original has passed saidscanning window, and means responsive to more than one required copybeing represented by said representing means for preventing thedeenergization of said exposure lamp until after said original haspassed said scanning window for the last time.
 8. A copying machine inaccordance with claim 3 further including means for preventing theoperation of said cutting means until a predetermined minimum length ofcopy paper has been fed from said roll, and means for controlling theoperation of said cutting means after a maximum length of copy paper hasbeen fed from said roll independent of the detection of the trailingedge of said original.
 9. A copying machine in accordance with claim 3further including deflector means for forming a slack portion in saidcopy paper between said paper roll feed initiating means and saidexposure window, said slack being taken up during any interval betweenthe stopping of said feed initiating means and the completion of theoperation of said cutting means.
 10. A copying machine in accordancewith claim 5 wherein said driven means controls the operation of saidautomatically initiating means at a time during its movement in saidsecond direction such that the ratio of the distance from the leadingedge of said original to that point in its forward path of movementwhere it becomes synchronized to movement of said copy paper to thedistance from said cutting means to that point in the copy paper path ofmovement where said copy paper becomes synchronized to forward movementof said original is equal to the ratio of the reverse speed of saidoriginal to the forward speed of said original.
 11. A copying machinecomprising a scanning window, means for controlling the transport of anoriginal document to be copied in the forward direction past saidscanning window, an exposure window, means for transporting copy paperpast said exposure window in synchronism with the forward movement ofsaid original past said scanning window, means for scanning saidoriginal at said scanning window and in response thereto for exposingsaid copy paper at said exposure window, means for controlling thetransport of said original in the reverse direction past said scanningwindow to permit another forward movement of said original past saidscanning window and another exposure of copy paper at said exposurewindow in response thereto, said reverse transport controlling meansbeing operative to control movement of said original past said scanningwindow at a speed greater than the speed at which said original movespast said scanning window in the forward direction, and means forinitiating the operation of said copy paper transporting means whilesaid original is being transported in the reverse direction past saidscanning window at a time such that when said original starts to betransported in the forward direction the leading edges of said originaland said copy paper are in optical synchronization.
 12. A copyingmachine in accordance with claim 11 further including means adapted tobe driven by said forward transport controlling means in response to thedetection of the leading edge of said original and for moving in a firstdirection while said original continues in its forward direction and forthereafter moving in a second opposite direction while said original ismoved in its reverse direction, and means responsive to the movement insaid second direction of said driven means for operating said initiatingmeans.
 13. A copying machine in accordance with claim 11 wherein saidinitiating means operates at a time during the reverse movement of saidoriginal such that the loading edge of said copy paper is insynchronization with the leading edge of said original at the same timethat the leading edge of said original moving in said reverse directionreaches the front edge of said scanning window, and further includingmeans responsive to the leading edge of said original rEaching the frontedge of said scanning window for deenergizing said reverse transportcontrolling means and for enabling the operation of said forwardtransport controlling means.
 14. A copying machine in accordance withclaim 11 wherein said scanning and exposing means includes an exposurelamp, means for energizing said lamp before the leading edge of saidoriginal reaches the front edge of said scanning window and formaintaining said lamp energized until the trailing edge of said originalhas passed said scanning window, and means responsive to more than onecopy of said original being made by the machine for preventing thedeenergization of said exposure lamp until after said original haspassed said scanning window in the forward direction a number of timesequal to the number of times equal to the number of copies being made.15. A copying machine in accordance with claim 11 further including acopy paper roll, means for feeding paper from said copy paper roll tosaid copy paper transporting means, means for cutting a sheet from saidcopy paper roll and for stopping the feed of copy paper from said rollresponsive to the length of copy paper fed from said roll being equal tothe length of said original, means for preventing the operation of saidcutting and stopping means until a predetermine minimum length of copypaper has been fed from said roll, and means for controlling theoperation of said cutting and stopping means after a maximum length ofcopy paper has been fed from said roll independent of the length of saidoriginal.
 16. A copying machine comprising a scanning window, means forcontrolling the transport of an original document to be copied in theforward direction past said scanning window, means for making a copy ofsaid original responsive to each forward pass of said original past saidscanning window, means for controlling the transport of said original inthe reverse direction past said scanning window in preparation for themaking of another copy, means for deenergizing said forward transportcontrolling means and for energizing said reverse transport controllingmeans responsive to the trailing edge of said original just clearing therear edge of said scanning window, and means for deenergizing saidreverse transport controlling means and for energizing said forwardtransport controlling means responsive to the leading edge of saidoriginal just clearing the front edge of said scanning window.
 17. Acopying machine in accordance with claim 16 wherein said reversetransport controlling means controls the movement of said original at aspeed greater than the speed of said original controlled by said forwardtransport controlling means.
 18. A copying machine in accordance withclaim 17 wherein said copy making means includes a supply of copy paperand means for initiating movement of a sheet of said copy paper duringreverse movement of said original such that when said original startsmoving in the forward direction said original and said copy sheet are incopy making synchronism.
 19. A copying machine in accordance with claim18 wherein said copy making means includes an exposure window past whichsaid copy sheet is moved, and said copy sheet movement initiating meansoperates at a time during the reverse movement of said original when thedistance between the leading edge of said original and that point in itsforward path of movement where it becomes synchronized to movement ofsaid copy sheet divided by said reverse speed is equal to the distancebetween the leading edge of said copy sheet and that point in the copysheet path of movement where said copy sheet becomes synchronized toforward movement of said original divided by the speed of movement ofsaid copy sheet.
 20. A copying machine comprising a scanning window,means for controlling the transport of an original document to be copiedin the forward direction past said scanning window, means forcontrolling the transport of said original in the reverse dIrection pastsaid scanning window, an exposure window, means for transporting copypaper past said exposure window, first means responsive to said originalbeing first inserted in the machine for initiating the transport of copypaper by said copy paper transporting means at a time such that theleading edge of said original within said scanning window is insynchronization with the leading edge of said copy paper within saidexposure window, means responsive to the trailing edge of said originalclearing said scanning window for deenergizing said forward transportcontrolling means and for energizing said reverse transport controllingmeans, second means for initiating the transport of copy paper by saidcopy paper transporting means during reverse movement of said originalpast said scanning window prior to the clearing of said scanning windowby said original, and means for deenergizing said reverse transportcontrolling means and energizing said forward transport controllingmeans at a time when forward movement of said original will cause it tobe in synchronization with movement of said copy paper.
 21. A copyingmachine in accordance with claim 20 wherein said second means operatesat a time during reverse movement of said original when the leading edgeof said original has not yet reached the rear edge of said scanningwindow.
 22. A copying machine in accordance with claim 21 wherein saidreverse transport controlling means controls movement of said originalpast said scanning window at a speed greater than the speed of saidoriginal controlled by said forward transport controlling means.
 23. Acopying machine in accordance with claim 20 wherein said means fordeenergizing said reverse transport controlling means and for energizingsaid forward transport controlling means operates responsive to theleading edge of said original having just cleared the forward edge ofsaid scanning window in the reverse direction.
 24. A copying machine inaccordance with claim 21 wherein said means for deenergizing saidreverse transport controlling means and for energizing said forwardtransport controlling means operates responsive to the leading edge ofsaid original having just cleared the forward edge of said scanningwindow in the reverse direction.
 25. A copying machine in accordancewith claim 20 wherein said reverse transport controlling means controlsmovement of said original past said scanning window at a speed greaterthan the speed of said original controlled by said forward transportcontrolling means.
 26. A copying machine in accordance with claim 25wherein said means for deenergizing said reverse transport controllingmeans and for energizing said forward transport controlling meansoperates responsive to the leading edge of said original having justcleared the forward edge of said scanning window in the reversedirection.
 27. A copying machine in accordance with claim 20 furtherincluding a roll of copy paper, said first and second initiating meanscontrolling the feed of copy paper from said roll to said copy papertransporting means, said first means being operative to initiate thefeeding of copy paper from said copy paper roll responsive to thedetection of the leading edge of said original, and means responsive tothe detection by said first means of the trailing edge of said originalfor cutting the copy paper fed from said roll and for stopping furtherfeed of copy paper from said roll.
 28. A copying machine in accordancewith claim 27 wherein said second means includes means adapted to bedriven in synchronism with said forward and reverse transportcontrolling means, means responsive to the detection of the leading edgeof said original for controlling the forward driving of said drivenmeans in synchronism with said forward transport controlling means, saiddriven means thereafter being driven in its reverse direction insynchronism with said reverse transport controlling means responsive tothe energization of said reverse transpoRt controlling means and thedeenergization of said forward transport controlling means, and meansresponsive to the return of said driven means to predetermined point inits path of reverse movement for initiating the feed of copy paper fromsaid copy paper roll.
 29. A copy machine in accordance with claim 28wherein said predetermined point in the path of reverse movement of saiddriven means is such that when said point is reached the leading edge ofsaid original has not yet reached the rear edge of said scanning window.30. A copying machine in accordance with claim 28 wherein said reversetransport controlling means controls reverse movement of said originalat a speed greater than the forward speed of said original controlled bysaid forward transport controlling means, said copy paper transportingmeans transports said copy paper at a speed equal to the forward speedof said original, and said predetermined point in the path of reversemovement of said driven means is such that between the time that saidpoint is reached and the time that said reverse transport controllingmeans is deenergized said original moves an amount in the reversedirection such that its subsequent forward movement is insynchronization with movement of said copy paper.
 31. A copying machinein accordance with claim 30 further including means for representing thenumber of copies required of said original, and means for dischargingsaid original from the machine in accordance with the number representedby said representing means after the required number of copies have beenmade.
 32. A copying machine in accordance with claim 27 furtherincluding means for preventing the stopping of said paper feed from saidroll and the operation of said cutting means until a predeterminedminimum length of copy paper has been fed from said roll, and means forcontrolling the stopping of said paper feed from said roll and theoperation of said cutting means after a maximum length of copy paper hasbeen fed from said roll independent of the detection of the trailingedge of said original by said first means.
 33. A copying machine inaccordance with claim 27 further including means for forming a slackportion in said copy paper between said cutting means and said exposurewindow, said slack being taken up during any interval between thestopping of the feed of said copy paper roll and the completion of theoperation of said cutting means.
 34. A copying machine in accordancewith claim 27 further including means for representing the number ofcopies required of said original, and means for discharging saidoriginal from the machine in accordance with the number represented bysaid representing means after the required number of copies have beenmade.
 35. A copying machine in accordance with claim 34 furtherincluding a lamp for reflecting light from said original as it passessaid scanning window toward said copy paper as it passes said exposurewindow, means for energizing said lamp before the leading edge of saidoriginal reaches the front edge of said scanning window, and meansresponsive only to said original having passed said scanning window inthe forward direction a number of times equal to the number representedby said representing means for deenergizing said lamp.
 36. A copyingmachine comprising a scanning window, means for controlling thetransport of an original document to be copied in the forward directionpast said scanning window, means for controlling the transport of saidoriginal in the reverse direction past said scanning window, an exposurewindow, means for transporting copy paper past said exposure window,first means in the forward path of movement of said original documentfor sensing said original document when it is first is inserted in themachine to initiate the transport of copy paper by said copy papertransporting means at a time such that the leading edge of said originalwithin said scanning window is in synchronization with the leading edgeof Said copy paper within said exposure window, means for scanning saidoriginal within said scanning window and exposing said copy paper withinsaid exposure window, means operative after the scanning of saidoriginal and exposure of said copy paper are completed for deenergizingsaid forward transport controlling means and for energizing said reversetransport controlling means, second means for initiating the transportof copy paper by said copy paper transporting means during reversemovement of said original past said scanning window prior to thecompletion thereof, and means for deenergizing said reverse transportcontrolling means and energizing said forward transport controllingmeans at a time when forward movement of said original will cause it tobe in synchronization with movement of said copy paper.
 37. A copyingmachine in accordance with claim 36 wherein said means for deenergizingsaid reverse transport controlling means and energizing said forwardtransport controlling means operates prior to return of the original tothat position at which said first means is operative when said originalis first inserted in the machine.
 38. A copying machine in accordancewith claim 36 further including a roll of copy paper, said copy papertransporting means including means for feeding copy paper from said rolland means for moving copy paper fed from said roll to said exposurewindow, means responsive to the operation of said first means foroperating said copy paper feeding means, means disposed between saidfeeding means and said moving means for cutting a copy sheet from copypaper fed from said roll, means for inhibiting the operation of saidfeeding means and controlling the operation of said cutting means suchthat the length of the cut copy sheet is equal to that of the original,and deflector means for forming a slack portion in said copy paperbetween said cutting means and said exposure window, the total slackportion formed being at least as great as the slack taken up during anyinterval between the stopping of said feeding means and the completionof the operation of said cutting means to permit continued normaloperation of said moving means while said copy paper is being cut.
 39. Acopying machine in accordance with claim 38 wherein said feeding meansis a pair of rollers and said moving means includes a pair of rollersdisposed between said exposure window and said deflector means.